Vessels, such as boats, ships, recreational watercraft, etc., suffer numerous deleterious effects due to contact with the fluid, i.e., water, in which the vessels operate. The effects include organism-based, e.g., barnacles, and electrical and/or chemical-based, e.g., wood rot, stray current and galvanic corrosion, effects upon the hull and other parts of the vessel. The conventional means of preventing or minimizing the effects involves removing the vessel from contact with water, i.e., to remove the vessel from the water in favor of storage on dry land.
Smaller vessels, such as boats and recreational watercraft, are often hauled out of water using trailers, boat lifting slings, or by forklifts and other such devices appropriate for removing the vessel from water and placing the vessel in dry storage. Larger vessels, such as ships, are moored in a dry dock location where the vessel is enclosed in a space forming a watertight chamber large enough for the vessel. Suitable size blocks support from beneath and make steady the vessel thereby allowing removal of water from the chamber via pumping or other mechanism resulting in dry storage of the vessel, e.g., a dry dock.
Other means of implementing dry storage of a vessel include suspending or raising vessels above contact with water by means of a lift. Smaller vessels, such as boats, are often raised from the water using various means in a location where they can be launched again. One approach is to install a derrick to raise the vessel by lifting bunkers beneath the vessel into contact with the vessel and raise the hull to a suitable height above the water. In other cases, the derrick uses fasteners attachable to a sling or fixed lifting points integral with the vessel and by securing the vessel as such the vessel is then raised away from the body of water a suitable distance and stored dry.
All of the aforementioned methods are used in one manner or another, however; these are not always convenient means for creating a dry storage condition due to a variety of logistical problems that come into effect such as those pertaining to time required to invoke such mechanisms, expense, availability of land or other resources for creating such storage, waterfront usage rules which may prohibit building or deploying such equipment, etc. For at least these reasons, in some cases it is more convenient for the owner of the vessel to leave the vessel moored or anchored and afloat in the body of water from whence the owner would re-launch the vessel.
Disadvantageously as described above, leaving the vessel exposed to water allows a variety of deleterious conditions to set in about the hull of the vessel and appendages connected both to and through the hull. These conditions include galvanic corrosion between dissimilar metals of the vessel having an electrical connection between them and where the water with which the metals contact acts as an electrolyte. Additionally, some vessels have electrically bonded metal fittings exposed through the vessel hull and contact with water by the fittings can act as a path to ground whenever those conditions are prevalent; stray current corrosion occurs in such instances between the vessel and ground by way of the exposed metal fitting.
Another deleterious condition is fouling of the vessel below the waterline related to marine plant and animal life affixing to the vessel's hull and/or appendages and whereby plant and animal growth adversely impacts the vessel's performance and further causes damage to the vessel. Another condition is foundering of the vessel in cases where a leak in the vessel below the waterline thereby allows water into the vessel causing the vessel to sink and/or cause significant damage to the vessel and potentially total loss of the vessel. Additionally, in some cases where tidal action beaches a vessel from time to time, the hull and appendages contact surfaces over which the vessel typically floats. Some of these surfaces can be muddy or comprised of other materials that can become imbedded in sea chests and other intake that feed systems can be damaged or whose performance may be affected if such material is fed to them.
Previous inventions utilizing a vessel hull cover can be divided into two basic categories. A first category secures a cover made of a flexible and “waterproof” material to the vessel itself by a securing mechanism depending on the vessel size and construction. The devices used range from simple lines acting as straps fastened topside to nailed battens in the case of wooden hulled ships of over a century ago.
The second category fastens the flexible, waterproof material to a frame apparatus of some sort positioned about the vessel whose principal aim is to ease the burden of deploying the hull cover. Some frame-based designs preclude light or rainwater from entering into the envelope itself.
In the former category, patents such as those issued to Duncan (U.S. Pat. No. 373,133, hereafter referred to as Duncan), Quimby (U.S. Pat. No. 623,961, hereafter referred to as Quimby), Farley (U.S. Pat. No. 632,919, hereafter referred to as Farley), Fisher (U.S. Pat. No. 3,142,283, hereafter referred to as Fisher), Liddell (U.S. Pat. No. 3,581,505, hereafter referred to as Liddell), Zondek (U.S. Pat. No. 3,761,334, hereafter referred to as Zondek), Cox (U.S. Pat. No. 4,026,233, hereafter referred to as Cox), and Preiser et al. (U.S. Pat. No. 4,046,094, hereafter referred to as Preiser) include enclosures for the bottom of vessels or parts thereof which are expressly designed to be entirely supported by rigging or means of fastening to attach the enclosure to the vessel and not to any other object such as a frame, dock, pier, pilings, or buoys when deployed as intended. None of the first category patents endeavor to remove water completely from between the entire vessel below the waterline and the enclosure. Nor are the enclosures designed with the intention to vacuum form fit to the dimensions of the vessel beneath the waterline while the vessel is afloat.
Duncan describes a cover applied to the length of the vessel to salvage ships that have run aground and foundered with holes in the hull below the waterline. The vessel supports the cover. Duncan fails to describe enclosing the entire hull and creating an envelope about the entire vessel, and the description of removing water between the hull and the cover by “squeezing” does not envision dry docking the vessel's entire hull while afloat.
Quimby describes a complete hull enclosure supported by the vessel and constructed from a waterproof fabric. Straps or ropes tied off at rings in the upper hem of the enclosure fasten the enclosure to cleats or other hardware mounted to the vessel. Quimby describes dewatering areas between the hull and the cover by means of pulling the case up tight in order to expel a portion of the water. Quimby further describes sealing off the case at the rear of the vessel by lacing the two open ends together to prevent an inflow of water. The cover is awkward to deploy in that the inventor describes teams in boats to deploy it, and in any case requires lacing the enclosure together about the stern of the vessel, which often enough will require some individual to get in the water to tie the enclosure. Quimby fails to describe using a pump or other siphoning or fluid evacuating device to lay up the entire hull in an effective dry dock condition.
Farley describes in one embodiment a jacket suspended by the vessel and encompassing the hull for the purpose of applying heat to the water within the jacket in which the ship's hull is enclosed. The heat destroys marine growth attached to the hull. Farley does not describe evacuating the hull or protecting metal parts from galvanic or stray current corrosion, nor would it provide such protection by leaving all parts exposed to water within the deployed jacket.
Fisher describes a hull enclosure completely supported by the vessel and also discusses applying a pump to remove brackish or saltwater from within the enclosure only to be replaced with freshwater. Fisher keeps the vessel encased in a bath of freshwater treated with chemical compounds to kill water-born plant and animal life. Because the vessel remains afloat in contact with water, Fisher does not protect propulsion and steering equipment from electrical or chemical effects.
Liddell describes a method for preventing fouling of barges, boats, piers and bulkheads among other objects by means of creating stagnant water zones. Battens are fastened atop the flexible waterproof material by a suitable securing mechanism, including nailing or screwing to wood structures and hulls. The intention is to reduce fouling of the structure by covering and leaving the water to stagnate within the space between the structure and the sectional covered area. The Liddell system is more awkward to deploy than many of the other approaches described herein. Battens need to be affixed about the hull while afloat presumably by a person getting into the water and working below the waterline of the vessel to attach the battens. The means of attaching the battens is cumbersome and uses nails or screws to affix the battens which may damage the vessel's hull. Such methods are inappropriate for other materials used to construct hulls such as fiberglass and metals. Furthermore, the cover envisioned by Liddell fails to offer protection against galvanic or stray current corrosion.
Zondek describes a means of covering a vessel's hull with metal foil for removing water from between a plate and the hull. The plates are held in place by adhesive and rolled onto the hull while the vessel is in dry dock. Zondek protects the hull only and not the propulsion equipment. In fact, the metal foil tends to aggravate stray current or galvanic corrosion. The metal foil is cumbersome to apply and remains in place for extended periods of time.
Cox describes a cover similar to Duncan in that a hole in the hull of a boat is temporarily shored from the vessel exterior by fitting a flexible material over the hole. The material is tied off to the bow of the boat and drapes back beneath the vessel's hull and covers the hole while retaining the material side edges above the waterline. The material stops short of the boat propulsion equipment enabling the propulsion equipment, if still operable, to drive the vessel and provide motion for applying pressure to the material covering the hull. The system is not intended to lay up the boat in a dry dock and is not used for storage or corrosion and fouling prevention.
Preiser et al. describes a method of suspending a shroud curtain about the periphery of a floating vessel. Pipes beneath the vessel pump in fresh water along the keel and the fresh water rises from the keel to the surface within the shroud curtain inhibiting marine growth. The method relies on using a large quantity of freshwater, which may be hard to come by and fails to inhibit the corrosive electrical conditions previously described.
In the latter category of prior approaches creating a structure or relying on a structure separate from the vessel, several prior approaches create enclosures about the bottom of vessels or parts thereof which are expressly designed to be entirely supported by rigging or means of fastening to attach the device to a frame or system not part of the vessel. Such frames or systems have been devised in a variety of ways including, but not limited to, connecting a flexible waterproof sheet to custom frames, docks, piers, pilings, or buoys when deployed as intended.
The latter category includes U.S. Patents issued to Wood (U.S. Pat. No. 3,685,477, hereafter referred to as Wood), Jackson (U.S. Pat. No. 4,282,822, hereafter referred to as Jackson), Eichert (U.S. Pat. No. 5,138,963, hereafter referred to as Eichert), Bradley (U.S. Pat. No. 5,152,242, hereafter referred to as Bradley), Perez-Collazo (U.S. Pat. No. 5,279,244, hereafter referred to as Perez-Collazo '244), Falcaro (U.S. Pat. No. 5,465,676, hereafter referred to as Falcaro), Faidi (U.S. Pat. No. 5,549,069, hereafter referred to as Faidi), and Perez-Collazo (U.S. Pat. No. 6,152,061, hereafter referred to as Perez-Collazo '061). Each of these references describe enclosures about the bottom of vessels or parts thereof expressly designed to be entirely supported by rigging or means of fastening attached to a frame or system not part of the vessel. As described above, the frame is designed for connection to a frame, dock, pier, etc.
Wood describes a floating, hinged frame connected to a dock and having a flexible bag attached to the frame. A hinged gate on one end of the frame is movable to provide access to and from the bag. Wood's device does not protect against electrical corrosion destroying propulsion and steering equipment and poses the general problems related to frame-type designs as described below.
Jackson describes another such device incredibly complex in its use of switches, inflatable toroidal bladders, pumping and ballasting systems for deploying a system which rises from beneath the vessel. Jackson's bladders fit the vessel periphery in an overlarge fashion and attach to the flexible material deploying them and forming the hull enclosure. The device fails to provide protection against galvanic and stray current corrosion. A pump-out evacuates seawater such that freshwater, treated with chemicals for preventing growth of marine born organisms, is introduced. The hole location for the pump's suction line is inflexibly located at a fixed location causing difficulties for deployment in a number of configurations. Depending on how the material fits the boat hull at any given time pockets of water may form in unwanted locations difficult or impossible to dewater and fail to provide sufficient lay up conditions to protect propulsion and control equipment of the vessel beneath the waterline from electrical corrosion or marine growth. Jackson fails to describe an additional system to dewater and includes an approach to dewatering the bag which facilitates substitution of sea water for freshwater.
Eichert describes a flexible hull enclosure as part of a more comprehensive maintenance facility. The enclosure keeps the vessel hull exposed to water within the enclosure and uses a pump with a drain hole and hose attached through the exterior of the material to remove sediment and debris removed from the vessel during painting and preservation work. The vessel is not protected from fouling or corrosion by use of the described complex enclosure.
Bradley, similar to Jackson above, describes an enclosure rising and falling from a position beneath the vessel in order to deploy or release the enclosure from use and relies on arrangements involving components other than the vessel for operation and support. Bradley describes a method for reducing hull fouling but fails to protect the metal components beneath the vessel's waterline from being subject to galvanic corrosion.
Perez-Collazo '244 describes a pulley system affixed to pilings in order to raise from beneath the vessel a flexible cover about the periphery of the vessel. The Perez-Collazo '244 system fails to evacuate water from contact with the hull and protect components beneath the waterline from galvanic corrosion.
Falcaro uses bubble wrap held up by buoyant PVC pipes filled with foam to produce a floating hull squeegee wiping the hull of debris each time the boat is launched from or docked to the device. The device fails to prevent the submersed metal components beneath the waterline from galvanic and stray current corrosion and fails to exsiccate the hull and remove the hull from contact with water. Hence, pockets of water are in contact with the hull which fails to prevent marine organism growth and development to the extent that the bubble wrap squeegee fails to dislodge them.
Faidi describes an external apparatus separate from the vessel and provides a frame structure to which the hull cover attaches in all described embodiments. Faidi employs a gate feature whereby the flexible material raises or lowers to allow entry of the vessel while held in place by the flexible material's frame structure separate from the vessel. Faidi, as with Jackson before him, describes pumping water from the interior of a frame fit enclosure and the hull of a boat with all that feature's attendant benefits; however, similar to Jackson, Faidi's system fits the flexible material to a frame apparatus, albeit one remaining above water rather than one which rises from beneath the water and vessel. Due to the use of a frame for support of the flexible material, Faidi requires comparatively more of the flexible material to cover the same size boat and thereby increases the cost of protecting the vessel. Additionally, Faidi's flexible material needs are larger than other frame fit enclosures in order to provide adequate room for docking the vessel while allowing for the cover to be completely pumped down, i.e., water removed from between the cover and vessel. Disadvantageously, in order to prevent stretching the material between the hull and the cover frame much more material is needed for the cover. If Faidi used less material, either the material would stretch at the periphery, thereby damaging the material or the frame more rapidly over time, or the frame holding the material in place would have to be smaller, increasing the difficulty of maneuvering in and out of the cover.
Perez-Collazo '061 describes another fixed deployment flexible hull cover system creating a floating bath environment treated with chemicals to inhibit marine growth. In addition to the above-described problems, the floating chemical bath fails to protect against galvanic corrosion of the vessel's water exposed metal parts.
As described above with respect to prior approaches, there are disadvantages to affixing hull covers to frames or structures separate from the vessel. In some instances, space limitations and minimal available room for deployment make installation or deployment awkward or not practical. Some approaches require creating complicated rigging systems made fast to piers, docks, bulkheads or other fixtures inaccessible or unusable for these purposes either because of construction, physical condition, or because permission from another party to make such arrangements is required.
In still other instances, ancillary structure-supported designs rely on electrical power and circuitry to operate pumps and switches as part of ballasting, pneumatic and hydraulic systems to create or deplete buoyancy of systems for deploying the system and setting the vessel into a lay up condition or providing for re-launching. Such additional circuitry adds complexity, increases cost, requires maintenance and replacement and creates a dependency such that a malfunctioning system may not work properly, if at all. A further disadvantage is that more material is required than in the previously described vessel supported hull cover systems. The additional material requirement is not just in the form of rigging, tackle, and construction materials for the frame, e.g., pontoons, floats, weights, brackets, pipes, hoses and other described hardware, but also in the amount of material required by the cover to encompass the hull depending on the dimensions of the frame structure with respect to the hull application.
Yet another disadvantage of separate frame structure systems is that they are subject to wave action imparting stress and abrasion on the flexible waterproof material as the cover floats independently of the vessel. This type of stress can rupture or damage the material thereby reducing or defeating the effectiveness of such designs.
Another disadvantage of separate frame structure systems is an awkwardness or inconvenience for a vessel operator in the course of maneuvering a vessel into such a system when the structure is set in a floating or otherwise suspended frame. Maneuvering a vessel is hazardous and cumbersome especially during docking and it is difficult enough to dock a vessel of any appreciable dimension during good conditions in a variety of common dock configurations, but a normal docking experience is only made worse by having the limited docking space even further reduced by installation of an additional frame structure within which the vessel is to be guided.